/Engine/Source/Runtime/Engine/Classes/Materials/MaterialRelevance.h
The class is only storing bits, initialized to 0 and has an |= operator to provide a combined set of multiple materials (component / mesh)
struct FMaterialRelevance
union FMaterial...
@2178
Bits that express which EMaterialShadingModel are used
uint8:  1
bDecal
uint8:  1
bDisableDepthTest
uint8:  1
bDistortion
uint8:  1
bHairStrands
uint8:  1
bHasVolumeMaterialDomain
uint8:  1
bMasked
uint8:  1
bNormalTranslucency
uint8:  1
bOpaque
uint8:  1
bOutputsTranslucentVelocity
uint8:  1
bPostMotionBlurTranslucency
uint8:  1
bSeparateTranslucency
uint8:  1
bTranslucencyModulate
uint8:  1
bTranslucentSurfaceLighting
uint8:  1
bTwoSided
uint8:  1
bUsesAnisotropy
uint8:  1
bUsesComplexSpecialRenderPath
uint8:  1
bUsesDisplacement
uint8:  1
bUsesDistanceCullFade
uint8:  1
bUsesGlobalDistanceField
uint8:  1
bUsesPixelDepthOffset
uint8:  1
bUsesSceneColorCopy
uint8:  1
bUsesSceneDepth
uint8:  1
bUsesSingleLayerWaterMaterial
uint8:  1
bUsesSkyMaterial
uint8:  1
bUsesWorldPositionOffset
uint8:  2
CustomDepthStencilUsageMask
uint64
Raw
uint16
ShadingModelMask
uint8
StrataBSDFCountMask
uint8
StrataUintPerPixel